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The researchers used an implant in the motor cortex of the brain – which controls the movement of limbs. Amazingly, once the device was implanted, it worked in the monkey without any training to help them to use it

The brain-spine interface uses a brain implant like this one to detect spiking activity of the brain's motor cortex. Pictured is the brain implant and a silicon model of a primate's brain

This pattern emulates the way a monkey would walk normally.

Previous research has shown similar implants can restore planning and movement in the control of robotic hands, and in one case, a patient's paralysed hand.

But the way leg muscles work is much more complex – and so a bigger challenge.

But as the surgery used components that have been approved for research in humans, the technology could be rapidly developed for human use.

The scale of disability globally caused by spinal cord paralysis is huge – between 250,000 and 500,000 people each year according to the World Health Organisation.

Two paralysed monkeys have been helped to walk using chips embedded in their brains. The animals displayed 'nearly normal locomotion' as the system decoded nerve activity and wirelessly transmitted signals that stimulated leg muscles

The system decodes activity from the brain's motor cortex and then relays this information to a system of electrodes located over the surface of the lumbar spinal cord, below the injury

As the surgery used components that have been approved for research in humans, the technology could be rapidly developed for human use. Grégoire Courtine is pictured holding a silicon model of a primate's brain and a brain implant

Around 37 per cent are caused by collisions with cars, 41 per cent caused by falls and 12 per cent due to sport.

Gregoire Courtine and colleagues tested the device in two Rhesus monkeys whose legs had been paralysed by a partial cutting of their spinal cords.

SPINAL CORD INJURIES

The scale of disability globally caused by spinal cord paralysis is huge – between 250,000 and 500,000 people each year according to the World Health Organisation.

In the UK spinal damage affects 1,000 people each year – mostly aged between 15 and 38.

And in the US, there are approximately 12,500 new cases each year.

Around 37 per cent are caused by collisions with cars, 41 per cent caused by falls and 12 per cent due to sport.

After being fitted with the devices, one of the monkeys regained some use of its paralysed leg within the first week after injury without training, both on a treadmill and on the ground.

The other monkey took two weeks to make a similar recovery, the research reported in Nature Communications said.

Professor Courtine, of the Swiss Federal Institute of Technology in Lausanne, said: 'This is the first time neuro-technology restores locomotion in primates.

'But there are many challenges ahead and it may take several years before all the components of this intervention can be tested in people.'

He added: 'To implement the brain-spine interface we developed an implantable, wireless system that operates in real-time and enabled a primate to behave freely without the constraint of tethered electronics.

Gregoire Courtine and colleagues tested the device in two Rhesus monkeys whose legs had been paralysed by a partial cutting of their spinal cords. Pictured is a silicon model of the brain, with the device attached

'We understood how to extract brain signals that encode flexion and extension movements of the leg with a mathematical algorithm.

'We then linked the decoded signals to the stimulation of specific hotspots in the spinal cord that induced the walking movement.'

Dr. Mark Bacon, Executive and Scientific Director at Spinal Research said: ‘Paralysed patients want to be able to regain real control, that is voluntary control of lost functions, like walking, and the use of implantable devices may be one way of achieving this.

‘But the technology solutions need to be powerful enough to manage natural movement, under voluntary control, in real time, whilst not being cumbersome or intrusive.

'That’s what will take it out of the lab and into the clinic. The current work is a clear demonstration that there is progress being made in the right direction.

'The fact that the components of the brain-spine interface are already approved for application in humans makes the translational pathway more straightforward and a proof concept study in patients may not be that far away.’

Andrew Jackson of Newcastle University, in a commentary, added that, given the rapid development of other similar neural devices from monkeys to humans in recent years, 'it is not unreasonable to speculate that we could see the first clinical demonstrations of interfaces between the brain and spinal cord by the end of the decade.'

The heart of the system was a pill-sized electrode array implanted in the brain that recorded signals from the motor cortex, the brain region responsible for voluntary movement

The research was carried out in China, but according to EU approved standards for a laboratory.

The researchers said that monkeys were used, rather than rodents, as they are very like humans in the way their brains activate during walking, how they recover from injury and the technology that is used would also be similar.

Dr Jackson said that it was 'notable' the research was carried out in China.

The implantable, wireless system operates in real-time and allows a monkey to behave freely without the constraint of tethered electronics

He said: 'The use of monkeys for neuroscience experiments continues to be questioned in the media, and animal-rights groups are making concerted efforts to ensure that restrictions on such work are tightened in both the United States and Europe.'

Many scientists may lack time, energy or resources to travel to China, he said.

The danger would be that 'there is thus a real danger that the development of treatments for debilitating neurological conditions will be delayed if high-quality, well-regulated research in monkeys cannot be performed in Europe and America owing to increasingly tight regulations.'

The researchers understood how to extract brain signals that encode flexion and extension movements of the leg with a mathematical algorithm. This allowed the, to link the decoded signals to the stimulation of specific hotspots in the spinal cord

Professor Simone Di Giovanni, Chair in Restorative Neuroscience at Imperial College London, who was not involved in the research, said the research was 'very promising and exciting' in an area of 'high priority.'

He said it was 'an important step forward in our understanding of how we could improve motor recovery in patients affected by spinal cord injury by using brain-spinal interface approaches.'

Before used in humans, more studies in larger numbers of animals would be necessary.

Researchers say that before use in humans, more studies in larger numbers of animals would be necessary. The device is pictured